Alstom designs and manufactures a wide range of trains. The aerodynamic specific topic of tunnel entry and crossing trains in tunnel is an important design topic for high speed train in terms of tympanic comfort and structure load because of complex pressure waves.

This presentation shows that this topic can be also important for urban trains like (metros and tramways). The pressure waves impact on equipment air inlets and outlet with additional pressure drop. The drag coefficient is also influenced by the aerodynamic of the crossing tramways in a short tunnel.

The STAR-CCM+® overset-mesh technology was used to achieve the CFD study.